The final report into last year’s CH-147F Chinook crash into the Ottawa River near Garrison Petawawa found none of the crew members on the training flight realized how quickly the helicopter was approaching the water in the moments before impact.
The two pilots, Capt. David Domagala, 32, and Capt. Marc Larouche, 53, were killed in the crash in the early hours of June 20, 2023.
Two flight engineers escaped with minor injuries, according to the preliminary Department of National Defence (DND) report into the crash, released last August. DND announced the end of its investigation in a news release Monday.
The 123-page final report, which doesn’t name any of the crew, explores how the flight likely went wrong as the instructor handed controls over to the student.
The helicopter was banking left at about 36 degrees but lacked sufficient thrust. It had also started dropping about 90 metres per minute at the handover, but there were no signs anyone aboard noticed the descent.
Investigators believe the crew must have thought they were at a steady altitude as they began lowering the aircraft further.
This map shows the helicopter’s planned route, from its ‘final approach and take off’ (FATO) area to a ‘confined’ training area. The Chinook crashed about 400 metres offshore. (Department of National Defence)
As the student took over, the crew was dealing with a simulated failure, checking a control advisory and moving over the dark, calm river — perfect conditions for a disorienting “black hole effect” that makes it harder to judge altitude using the naked eye.
The crew would have had to determine altitude by checking the helicopter’s instruments, but with everything going on the student was likely “task saturated” and more focused on speed than altitude. The instructor was also busy going over maps and checklists, according to the report.
With the helicopter dropping faster than the crew realized, a low altitude warning went off 7.5 seconds before impact at about 38 metres above the water.
One of the pilots cancelled the warning without taking further action, which the investigators attributed to the multiple distractions.
Two seconds before impact, one of the flight engineers looked out a side door and noted the helicopter was only six metres above the water surface.
The helicopter struck the Ottawa River about 400 metres offshore and sank about 25 metres to the riverbed, where it stayed for 23 days.
The rescue
The two survivors were thrown around the cabin with their tethers still attached. Both disconnected from the sinking helicopter and grabbed debris to help stay afloat. They weren’t wearing their damage-resistant life preservers — the report notes this was fairly common for comfort and range of motion.
As the survivors tired and began to cramp up, first responders rescued one using canoes they grabbed from the nearby shoreline. The other was plucked from the water by the crew of one of the base’s rescue boats.
First responders on shore pointed their vehicle headlights toward the river while another helicopter on a night training flight also helped light the scene.
WATCH | Scenes from the search in the hours after the crash:
The recommendations
Among the report’s many recommendations is a call for more instructors and aircraft for pilot training. A course that should have taken seven months took the student involved in the crash 18 months, and “this is not an exceptional situation,” according to the report.
Canada could also adopt disorientation training devices used by many allies, and refresh underwater escape training every five years instead of every 10.
Tactical aviation crew now have this training every five years, the report notes, and there have also been changes regarding altitude over water and reacting to altitude alerts.
The report recommends Garrison Petawawa get either more boats or bigger ones to be able to respond to a potential crash involving a number closer to the Chinook’s 37-person capacity, and for it to have more boat launch points.
The report also calls for more command centre resources. A command vehicle that was out of service for repairs contained maps and radios, forcing rescuers to turn to Facebook Messenger to communicate, “which is not an ideal situation to transmit sensitive information.”
Read the full crash report: